Cutting insert with internal coolant passages and method of making same

ABSTRACT

A cutting insert ( 100,100′ ) includes a body ( 102 ) having a top face ( 104 ), a bottom face ( 106 ) opposite the top face ( 104 ), and at least one flank face ( 108, 110, 112, 114 ). A coolant inlet aperture ( 126 ), a coolant outlet aperture ( 132, 134 ), and an internal coolant passage ( 128, 130 ) in fluid communication with the coolant inlet aperture ( 126 ) and the coolant outlet aperture ( 132, 134 ) are formed using electro-magnetic radiation. The coolant inlet aperture ( 126 ) can be formed in the top face ( 104 ), the bottom face ( 106 ) and/or the flank face ( 108, 110, 112, 114 ), and the coolant outlet aperture ( 132, 134 ) can be formed in any different face ( 104, 106, 108, 110, 112, 114 ). A method of forming the internal coolant passages ( 128, 130 ) is described.

RELATED APPLICATIONS

This application is a continuation of, and claims priority to, U.S.patent application Ser. No. 14/564,452, filed Dec. 9, 2014, the entiretyof which is incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a cutting insert used for chipforming andmaterial removal operations, as well as a method for making the cuttinginsert. More specifically, the invention pertains to a cutting insertused for chipforming and material removal operations, as well as amethod for making the cutting insert, wherein there is enhanced deliveryof coolant adjacent the interface between the cutting edge of thecutting insert and the workpiece (i.e., the cutting edge-chip interface)to diminish excessive heat at the cutting edge-chip interface. Thepresent invention relates to improved rotary tools and improved methodsof producing such rotary tools.

DESCRIPTION OF RELATED ART

In a chipforming and material removal operation (e.g., a millingoperation), heat is generated at the cutting edge-chip interface. It iswell-known that excessive heat at the cutting edge-chip interface cannegatively impact upon (i.e., reduce or shorten) the useful tool life ofthe cutting insert. As can be appreciated, a shorter useful tool lifeincreases overall operating costs and decreases overall productionefficiency. Hence, there are readily apparent advantages connected withproviding a cutting insert that facilitates a decrease of the heat atthe cutting edge-chip interface.

It is readily apparent that in a chipforming and material removaloperation, higher operating temperatures at the cutting edge-chipinterface can have a detrimental impact on the useful tool life. Thesehigher temperatures can cause premature breakage and/or excessive wear,which results in reduction or shortening of the useful tool life. Ittherefore would be highly desirable to provide a cutting insert used forchip forming and material removal operations wherein there is animproved delivery of coolant to the cutting edge-chip interface.

In a cutting operation (e.g., turning operation or milling operation),the chip generated from the workpiece can sometimes stick (e.g., throughwelding) to the surface of the cutting insert (e.g., a turning insert ora milling insert). The build up of chip material on the cutting insertin this fashion is an undesirable occurrence that can negatively impactupon the performance of the cutting insert, and hence, the overallmaterial removal operation. Thus, it would be highly desirable toprovide a cutting inert (e.g., a turning insert or a milling insert),used for chipforming and material removal operations wherein there isenhanced delivery of coolant to the cutting edge-chip interface so as toresult in enhanced lubrication at the cutting edge-chip interface. Theconsequence of enhanced lubrication at the cutting edge-chip interfaceis a decrease in the tendency of the chip to stick to the cuttinginsert.

In a cutting operation such as, for example, a milling operation, therecan occur instances in which the chips do not exit the region of thecutting edge-chip interface when the chip sticks to the cutting insert.When a chip does not exit the region of the cutting edge-chip interface,there is the potential that a chip can be re-cut. It is undesirable forthe cutting insert to re-cut a chip already removed from the workpiece.A flow of coolant to the cutting edge-chip interface will facilitate theevacuation of chips from the cutting edge-chip interface therebyminimizing the potential that a chip will be re-cut. Hence, it would behighly desirable to provide a cutting inert (e.g., a turning insert or amilling insert), used for chipforming and material removal operationswherein there is enhanced delivery of coolant to the cutting edge-chipinterface so as to reduce the potential that a chip will be re-cut. Theconsequence of enhanced flow of coolant to the cutting edge-chipinterface is better evacuation of chips from the vicinity of theinterface with a consequent reduction in the potential to re-cut a chip.

Powder metallurgical techniques typically can be useful to make acutting insert used for chip forming and material removal operations. Inthis regard, a powder mixture is pressed into a partially dense greencompact. Then, the green compact is subjected to a consolidationtreatment (e.g., vacuum sintering, pressure sintering, HIPing and thelike) to consolidate the green compact into a fully dense body. Whilethese powder metallurgical techniques are satisfactory, the use thereofto make cutting tools of a more complex geometry may raise amanufacturing challenge. It would thus be highly desirable to provide acutting insert (e.g., a turning insert or milling insert) used forchipforming and material removal operations wherein there is enhanceddelivery of coolant to the cutting edge-chip interface wherein thecutting insert is of a design, even though complex, that could be madevia methods such as, for example, injection molding.

SUMMARY OF THE INVENTION

The problem of delivering high-pressure coolant flow to the cuttingedge-chip interface is solved by providing one or more coolant holesthat are formed by a laser beam so that coolant can be delivereddirectly to the cutting edge-chip interface.

The key feature of this invention is to be able to create coolant holesin cutting tips directly offering design freedom and applicationflexibility to deliver coolant directly at the cutting edge of the tool.Currently, coolant delivery is limited to carbide or steel shank: fromwhich point we rely on pressure and/or flow rate to flood the cuttingvolume with coolant. This can be overcome by creating these coolantchannels in tips that transport the coolant directly to cutting area andin turn improving the mechanics of thermal equilibrium during metalcutting. The most important benefit of this invention is to assist withMQL (minimum quantity lubrication), ensure keeping pressure at anappropriate level and manipulate chip deformation, flow and evacuation.This concept will support the guidance of the required quantity oflubricant most effective to the desired area of the tool or work piece.It also eliminates the need to flood the cutting volume with coolant andin turn deliver desired/required amount of coolant to cutting areadirectly. Benefits are two-fold: 1. Savings through minimizing coolantuse and 2. Environmental impact.

In addition to the design aspect of the patent, focus also needs to bedirected at manufacturability of such a design and a cutting tool as awhole. Electro-magnetic radiation is used in various form bymanipulating the beam, and/or encasing the beam in a water-jet to makethe cutting tool as depicted in the drawings. The cutting tool of theinvention can be made by other means, such as a pressurized jet of afluid having abrasive embedded therein, ultrasonic waves, mechanicalvibrations, and the like. As used herein, electromagnetic radiation isdefined as radiation consisting of electromagnetic waves, includingradio waves, infrared, visible light, ultraviolet, x-rays and gammarays. The electro-magnetic radiation can be trepanned usinggalvanometers and/or passing them through rotating mirrors and/or usingit in conjunction with a water-jet either encompassed through a waterjet or used in addition to a water-jet to make the desired holes incutting tips. The hole sizes could vary from 50 microns to 5 mm in widthdepth 5 microns to 50 mm in depth.

The intent of the patent disclosure is to connect such a hole drilledusing the above technique to an existing coolant delivery channel thatis already pressed, formed or sintered into the shank of a round tool orholder of an insert. The selected manufacturing process allows to microdrill the nozzle and adjust its orientation angle and shape as requiredby a specific metal cutting operation. The localized volume removalensures that cutting edge is preserved even when the coolant channel ismachined in close proximity to the edge. Flexibility is built into theprocess as this can be applied to tipped inserts, inserts, round tools,tipped round tools, or any other cutting tool in various formats.

In one aspect of the invention, a method of manufacturing a cuttinginsert comprises: forming a coolant inlet aperture in one of the topface, the bottom face and the at least one flank face, at least oneinternal coolant passage in fluid communication with the coolant inletaperture, and a coolant outlet aperture in fluid communication with theat least one internal coolant passage, wherein the coolant inletaperture, the at least one internal coolant passage and the coolantoutlet aperture are formed by using electro-magnetic radiation.

In another aspect of the invention, a cutting insert is manufacturedusing the method described above.

In yet another aspect of the invention, a toolholder assembly comprisesa body portion and a cutting end portion extending from the bodyportion. The cutting end portion includes a pocket having a bottomsupport surface and at least one side support surface. A cutting insertis mounted in the pocket. The cutting insert has a top face, a bottomface opposite the top face, at least one flank face, a coolant inletaperture formed in one of the top face, the bottom face, and the atleast one flank face, a coolant outlet aperture formed in a differentone of the top face, the bottom face and the at least one of the flankface, and an internal coolant passage in fluid communication with thecoolant inlet aperture and the coolant outlet aperture, wherein thecoolant inlet aperture, the at least one internal coolant passage andthe coolant outlet aperture are formed by using electro-magneticradiation.

BRIEF DESCRIPTION OF THE DRAWINGS

While various embodiments of the invention are illustrated, theparticular embodiments shown should not be construed to limit theclaims. It is anticipated that various changes and modifications may bemade without departing from the scope of this invention.

FIG. 1 is a top view of one specific embodiment of a toolholder assemblywith coolant openings in a bottom support surface of the pocket and acutting insert with an internal coolant passage according to theinvention mounted in the pocket of the toolholder assembly;

FIG. 2 is a top view of the toolholder assembly of FIG. 1 with a cuttinginsert of the invention removed not mounted in the pocket of thetoolholder assembly to more clearly show the arcuate coolant opening inthe bottom support surface of the pocket;

FIG. 3 is an enlarged view of the pocket of the toolholder assembly ofFIG. 1 showing the arcuate coolant opening for supplying coolant to thecutting insert of the invention;

FIG. 4 is an isometric top view of the cutting insert manufactured usingthe method of the invention;

FIG. 5 is another isometric top view of the cutting insert manufacturedusing the method of the invention;

FIG. 6 is a top view of another specific embodiment of a toolholderassembly with coolant openings formed in the side support walls of thepocket and a cutting tip in a round tool according to the inventionmounted in the pocket of the toolholder assembly;

FIG. 7 is an isometric top view of a specific embodiment of a roundtoolholder assembly and a suitable cutting insert with internal coolantpassages formed by a laser technique according to the invention mountedin the pocket of the toolholder assembly; and

FIG. 8 is an enlarged view of the pocket of the round toolholderassembly of FIG. 7 with the cutting insert mounted in the pocket of thetoolholder assembly.

DETAILED DESCRIPTION

In the present description of non-limiting embodiments and in theclaims, other than in the operating examples or where otherwiseindicated, all numbers expressing quantities or characteristics ofingredients and products, processing conditions, and the like are to beunderstood as being modified in all instances by the term “about”.Accordingly, unless indicated to the contrary, any numerical parametersset forth in the following description and the attached claims areapproximations that may vary depending upon the desired properties oneseeks to obtain in the apparatus and methods according to the presentdisclosure. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Referring to the drawings, there should be an appreciation that thecutting insert of the invention, as well as the cutting assembly of theinvention, can operate in a number of different applications. Thecutting insert, which has internal coolant delivery, is for use in thechipforming removal of material from a workpiece. In this respect, thecutting insert is for use in a chipforming material removal operationwherein there is enhanced delivery of coolant adjacent the interfacebetween the cutting insert and the workpiece (i.e., the cuttingedge-chip interface) to diminish excessive heat at the cutting edge-chipinterface. The coolant channels can be drilled and applied to tippedround tools, where such a tip could be made of Superhard material, suchas Cubic Boron Nitride (CBN), Polycrystalline Cubic Boron Nitride(PCBN), Polycrystalline Diamonds (PCD), tungsten carbide (WC), cermet,ceramic, and the like.

The enhanced delivery of coolant to the cutting edge-chip interfaceleads to certain advantages. For example, enhanced delivery of coolantto the cutting edge-chip interface results in enhanced lubrication atthe cutting edge-chip interface which decreases the tendency of the chipto stick to the cutting insert. Further, enhanced flow of coolant to thecutting edge-chip interface leads to better evacuation of chips from thevicinity of the interface with a consequent reduction in the potentialto re-cut a chip.

As will be made apparent from the description hereinafter, the nature ofthe coolant dispersion or spray is such that it is continuous betweenthe adjacent so-called activated interior coolant passages. The coolantactually exits the activated coolant passages in the form of acontinuous cone of coolant. By providing such a coolant dispersion, thecutting insert achieves enhanced delivery of coolant to the cuttingedge-chip interface.

There should also be an appreciation that the interior coolant passagedischarge has an orientation whereby the coolant impinges beneath thechip surface. Such an orientation of the coolant enhances the coolingproperties, which enhances the overall performance of the cuttinginsert.

The description herein of specific applications should not be alimitation on the scope and extent of the use of the cutting insert.

In the chipforming material removal operation, a cutting insert 100engages a workpiece to remove material from a workpiece typically in theform of chips. A material removal operation that removes material fromthe workpiece in the form of chips typically is known by those skilledin the art as a chipforming material removal operation. The book MachineShop Practice [Industrial Press Inc., New York, N.Y. (1981)] byMoltrecht presents at pages 199-204 a description, inter alia, of chipformation, as well as different kinds of chips (i.e., continuous chip,discontinuous chip, segmental chip). Moltrecht reads [in part] at pages199-200, “When the cutting tool first makes contact with the metal, itcompresses the metal ahead of the cutting edge. As the tool advances,the metal ahead of the cutting edge is stressed to the point where itwill shear internally, causing the grains of the metal to deform and toflow plastically along a plane called the shear plane . . . When thetype of metal being cut is ductile, such as steel, the chip will comeoff in a continuous ribbon . . . ”. Moltrecht goes on to describeformation of a discontinuous chip and a segmented chip.

As another example, the text found at pages 302-315 of the ASTE ToolEngineers Handbook, McGraw Hill Book Co., New York, N.Y. (1949) providesa lengthy description of chip formation in the metal cutting process. Atpage 303, the ASTE Handbook makes the clear connection between chipformation and machining operations such as turning, milling anddrilling. The following patent documents discuss the formation of chipsin a material removal operation: U.S. Pat. No. 5,709,907 to Battaglia etal. (assigned to Kennametal Inc.), U.S. Pat. No. 5,722,803 to Battagliaet al. (assigned to Kennametal Inc.), and U.S. Pat. No. 6,161,990 toOles et al. (assigned to Kennametal Inc.).

Referring to the drawings, FIGS. 1-3 show a toolholder assemblygenerally designated as 10 according to an embodiment of the invention.The toolholder assembly 10 has a body portion 12 and a cutting endportion 14 extends in a radial outward fashion from the body portion 12.The cutting end portion 14 contains a pocket, shown generally at 16. Thepocket 16 includes a substantially planar bottom support surface 18 anda pair of side support surfaces 20, 22, as shown in FIG. 2. The bottomsupport surface 18 and the side support surfaces 20, 22 generallyconform to the shape of a cutting insert 100 to be mounted thereon.

The bottom support surface 18 contains at least one arcuate coolantopening 24 in fluid communication with a coolant passage 26. Coolantfrom a coolant source 28 enters the coolant passage 26 and travels so toexit at the arcuate coolant opening 24. Coolant exiting from the arcuatecoolant opening 24 then passes into the cutting insert 100, as will beset forth in more detail hereinafter. In the illustrated embodiment, thebottom support surface 18 contains two arcuate coolant openings 24located on opposite sides of a threaded bore 30. However, it will beappreciated that the invention is not limited by the number of coolantopenings 24, and that the invention can be practiced with any desirablenumber of coolant openings 24 for providing a sufficient coolant flowrate to a cutting insert 100.

In addition, there should be an appreciation that anyone of a number ofdifferent kinds of fluid or coolant are suitable for use in thetoolholder assembly 10 and the cutting insert 100. Broadly speaking,there are two basic categories of fluids or coolants; namely, oil-basedfluids which include straight oils and soluble oils, and chemical fluidswhich include synthetic and semisynthetic coolants. Straight oils arecomposed of a base mineral or petroleum oil and often contain polarlubricants such as fats, vegetable oils, and esters, as well as extremepressure additives of chlorine, sulfur and phosphorus. Soluble oils(also called emulsion fluid) are composed of a base of petroleum ormineral oil combined with emulsifiers and blending agents Petroleum ormineral oil combined with emulsifiers and blending agents are basiccomponents of soluble oils (also called emulsifiable oils). Theconcentration of listed components in their water mixture is usuallybetween 30-85%. Usually the soaps, wetting agents, and couplers are usedas emulsifiers, and their basic role is to reduce the surface tension.As a result, they can cause a fluid tendency to foam. In addition,soluble oils can contain oiliness agents such as ester, extreme pressureadditives, alkanolamines to provide reserve alkalinity, a biocide suchas triazine or oxazolidene, a defoamer, such as a long chain organicfatty alcohol or salt, corrosion inhibitors, antioxidants, etc.Synthetic fluids (chemical fluids) can be further categorized into twosubgroups: true solutions and surface active fluids. True solutionfluids are composed essentially of alkaline inorganic and organiccompounds and are formulated to impart corrosion protection to water.Chemical surface-active fluids are composed of alkaline inorganic andorganic corrosion inhibitors combined with anionic non-ionic wettingagents to provide lubrication and improve wetting ability.Extreme-pressure lubricants based on chlorine, sulfur, and phosphorus,as well as some of the more recently developed polymer physical extremepressure agents can be additionally incorporated in this fluids.Semisynthetics fluids (also called semi-chemical) contains a loweramount of refined base oil (5-30%) in the concentrate. They areadditionally mixed with emulsifiers, as well as 30-50% of water. Sincethey include both constituents of synthetic and soluble oils,characteristics properties common to both synthetics and water solubleoils are presented.

Referring now to FIGS. 4 and 5, the cutting insert 100 that is suitablefor use with the toolholder assembly 10 is shown according to anembodiment of the invention. It is typical that the cutting insert 100is made by a powder metallurgical technique. In this regard, thestarting powder components for the milling insert are first blended ormilled into a starting powder mixture. A lubricant or fugitive binder istypically included as a starting component. The starting powder mixtureis then pressed into the shape of a milling insert (i.e., a greencompact) that has partial density. The green compact is then subjectedto a consolidation treatment, typically at an elevated temperature andoptionally under pressure. The consolidation treatment can includepressure sintering, vacuum sintering, hot isostatic pressing and otherknown consolidation processes. The resultant article is an essentiallyfully dense post-consolidation milling insert. The post-consolidationmilling insert may be subjected to various finishing operations such asgrinding or blasting to the like to form an uncoated milling insert.

The uncoated cutting insert may be useful without a coating thereon. Inthe alternative, it may be beneficial to apply a coating scheme to theuncoated milling insert to form a coated milling insert. The coatingscheme can be anyone of a wide variety of suitable coating schemescomprising one or more separate coating layers and applied by anyone ormore of a wide variety of coating deposition techniques includingphysical vapor deposition (PVD) and chemical vapor deposition (CVD).

The cutting insert 100 may be made from one of any number of materialsthat are suitable for use as a cutting insert. The following materialsare exemplary materials useful for a cutting insert: tool steels,cemented carbides, and Superhard material, such as Cubic Boron Nitride(CBN), Polycrystalline Cubic Boron Nitride (PCBN), PolycrystallineDiamonds (PCD), tungsten carbide (WC), cermet, ceramic, and the like.The specific materials and combinations of materials depend upon thespecific application for the cutting insert 100.

In reference to tool steels, the following patent documents disclosetool steels suitable for use as a cutting insert: U.S. Pat. No.4,276,085 for High speed Steel, U.S. Pat. No. 4,880,461 for Superhardhigh-speed tool steel, and U.S. Pat. No. 5,252,119 for High Speed ToolSteel Produced by Sintered Powder and Method of Producing the Same. Inreference to cemented carbides, the following patent documents disclosecemented carbides suitable for use as a cutting insert: U.S. PatentApplication Publication No. US2006/0171837 A1 for a Cemented CarbideBody Containing Zirconium and Niobium and Method of Making the Same,U.S. Reissue Patent No. 34,180 for Preferentially Binder EnrichedCemented Carbide Bodies and Method of Manufacture, and U.S. Pat. No.5,955,186 for a Coated Cutting Insert with A C Porosity Substrate HavingNon-Stratified Surface Binder Enrichment. In reference to cermets, thefollowing patent documents disclose cermets suitable for use as acutting insert: U.S. Pat. No. 6,124,040 for Composite and Process forthe Production Thereof, and U.S. Pat. No. 6,010,283 for a Cutting Insertof a Cermet Having a Co—Ni—Fe Binder. In reference to ceramics, thefollowing patent documents disclose ceramics suitable for use as acutting insert: U.S. Pat. No. 5,024,976 for an Alumina-zirconia-siliconcarbide-magnesia Ceramic Cutting Tools, U.S. Pat. No. 4,880,755 for aSiAlON Cutting Tool Composition, U.S. Pat. No. 5,525,134 for a siliconNitride Ceramic and Cutting Tool made thereof, U.S. Pat. No. 6,905,992for a Ceramic Body Reinforced with Coarse Silicon Carbide Whiskers andMethod for Making the Same, and S.S. Patent No. 7,094,717 for a SiAlONContaining Ytterbium and Method of Making.

In general, the cutting insert 100 has a polygonal body 102 with acentral axis, A, (i.e., parallel to the z-axis) extending therethrough.In the illustrated embodiment, the cutting insert 100 is generallydiamond in shape with respective 80 degree and 100 degree opposite acuteand obtuse angles. The cutting insert 100 is symmetric about all threeaxes (x-, y- and z-axes). However, it will be appreciated that theinvention can be practiced with a nonsymmetric cutting insert 100 thatis any desirable shape, such as round, triangular, and the like.

The body 102 has a top face 104, an opposite bottom face 106, and aplurality of substantially planar flank faces 108, 110, 112, 114 joiningthe top and bottom faces 104, 106. In general, the top face 104 issubstantially identical to the bottom face 106, the flank face 108 issubstantially identical to the opposite flank face 112, and the flankface 110 is substantially identical to the opposite flank face 114. Inaddition, the plurality of flank faces 108, 110, 112, 114 aresubstantially perpendicular to the top and bottom faces 104, 106.However, it will be appreciated that the invention is not limited by thespecific geometric shape of the cutting insert 100, and that theinvention can be practiced with a cutting insert having nonperpendicularflank faces and non-identical opposite top and bottom and non-identicalopposite flank faces.

A substantially planar cutting edge 108 a, 110 a, 112 a, 114 a isdefined at the intersection between the top face 104 and a respectivesubstantially planar flank face 108, 110, 112, 114. Similarly, asubstantially planar cutting edge 108 b, 110 b, 112 b, 114 b is definedat the intersection between the bottom face 106 and a respectivesubstantially planar flank face 108, 110, 112, 114. However, it will beappreciated that the invention is not limited by the specific shape ofthe cutting edges, and that the invention can be practiced withnon-planar cutting edges.

The cutting insert 100 includes bidirectional acute cutting corners 116,118 and cutting edge corners 116 a, 118 a at the intersection betweenthe top face 104 and adjacent flank faces 108, 110, 112, 114, andbidirectional obtuse cutting corners 120, 122 and cutting edge corners120 a, 122 a at the intersection between the top face 104 and adjacentflank faces 108, 110, 112, 114. Similarly, cutting insert 100 includesbidirectional acute cutting corners 116 b, 118 b at the intersectionbetween the bottom face 106 and adjacent flank faces 108, 110, 112, 114,and bidirectional obtuse cutting corners 120 b, 122 b at theintersection between the bottom face 106 and adjacent flank faces 108,110, 112, 114. The purpose of bidirectional acute cutting corners 116 a,116 b, 118 a, 118 b is for primary cutting and the purpose of thebidirectional obtuse cutting corners 120 a, 120 b, 122 a, 122 b is forcreating chamfers.

For the specific embodiment shown in the figures, a central aperture 124is provided through the cutting insert 100 for retention of the insertwithin the toolholder assembly 100. In another embodiment, the cuttinginsert 100 does not include an aperture 124 for securing the cuttinginsert 100 to the toolholder assembly 10. Rather, the cutting insert 100is retained in the toolholder assembly 10 by a clamping mechanism 32,which securely retains the cutting insert 100 within the toolholderassembly 10, as shown in FIGS. 1 and 6.

One aspect of the invention is that the cutting insert 100 includes atleast one coolant inlet aperture 126 formed in the top face 104, thebottom face 106, or both, that is in fluid communication with the atleast one arcuate coolant opening 24 formed in the bottom supportsurface 18 when the cutting insert 100 is mounted in the pocket 16 ofthe toolholder assembly 10. Thus, the purpose of the coolant inletaperture 126 is to serve as a coolant inlet for the cutting insert 100.

The cutting insert 100 further includes at least one internal coolantpassage 128, 130 in fluid communication with the coolant inlet aperture126. In the illustrated embodiment, the cutting insert 100 includes apair of internal coolant passages 128, 130. One internal coolant passage128 extends from the coolant inlet aperture 126 to a coolant outletaperture 132 formed in the top face 104 proximate the cutting edge 108 aof the cutting insert 110. The other internal coolant passage 130extends from the coolant inlet aperture 126 to a coolant outlet aperture134 formed in the flank face 108 proximate the cutting edge 108 a of thecutting insert 100. It should be realized that the invention is notlimited by the number of coolant inlet apertures 126 formed in the topface 104 and/or the bottom face 106 of the cutting insert 100, and thatthe invention can be practiced with any desirable number of coolantinlet apertures 126 for providing sufficient coolant to the cuttingedge-chip interface. In addition, it will be appreciated that theinvention is not limited by the number of internal coolant passages 128,130, and that the invention can be practiced with any desirable numberof internal coolant passages in fluid communication with any desirablenumber of coolant inlet apertures to provide sufficient coolant to thecutting edge-chip interface.

Another aspect of the invention is that the coolant inlet aperture 126,internal coolant passages 128, 130 and coolant outlet apertures 132, 134are formed using a laser beam technique. One advantage of using a laserbeam technique is that the apertures and passages can be preciselyformed with any desirable cross-sectional shape and diameter. Forexample, the apertures and passages can be circular in cross-sectionalshape with a relatively small diameter of about 5 microns. In anotherexample, the apertures and passages can be non-circular incross-sectional shape with a relatively larger diameter of between about10 microns to about 100 microns.

One laser beam technique to produce the coolant inlet and outletapertures 126, 132, 134 and the internal coolant passages 128, 130 isknown as Laser MicroJet® that is commercially available from SYNOVAlocated in Ecublens, Switzerland (www.synova.ch). In general, LaserMicroJet® technology combines a laser beam with a low-pressure, purede-ionized and filtered water jet, which cools the cutting surface andoffers extreme precision debris removal. Laser MicroJet® technologyinvolves generating a water jet using small nozzles (20-160 μm) made ofsapphire or diamond, and low water pressure (100-300 bar). The water jetis not involved in the cutting operation. A high-power pulsed laser beamis focused into a nozzle in a water chamber. Lasers are pulsed with apulse duration in the micro- or nano-second range, for example, 10 fs to1 millisecond, and operating at a frequency of 1064 nm (IR), 532 nm(Green), or 355 nm (UV). The laser beam is guided by total interreflection at the water/air interface, in a manner similar toconventional glass fibers, to a disk of super hard material, such asCubic Boron Nitride (CBN), Polycrystalline Diamonds (PCD), tungstencarbide (WC), and the like. Laser MicroJet® technology has a longworking distance (>100 mm).

Another similar laser beam technique using laser ablation by encasing alaser beam in a water jet is commercially available from Avonisys AGlocated in Zug, Switzerland (http://www.avonisys.com).

Another laser beam technique is commercially available from GFH GmbHlocated in Deggenforf, Germany (www.gfh-gmbh.de). This laser beamtechnique uses a rotating telescope of cylindrical lenses that causesrotation of the laser beam to produce a laser beam that is substantiallyuniform in power density. As a result, this laser beam technique canproduce positive conical bores in which the entrance diameter is largerthan the outlet diameter, a cylindrical bore in which the entrance andoutlet diameters are equal, or negative conical bores in which theentrance diameter is smaller than the outlet diameter. The resultingbores are free of burrs and have a roundness of +/−1%.

Another laser beam technique is to use a machine equipped with agalvanometer to machine the three-dimensional cavities that make thehelical flute. However, a laser beam with a variety of energy intensitydistribution profiles can be adapted to achieve the best topography inthe three-dimensional cavity and the cutting edge. It should beappreciated that this technique is not limited to a Gaussian laser beamprofile, and that the invention can be practiced using Top-Hat or Squareintensity profiles.

As described above, the bottom support surface 18 of the toolholderassembly 10 contains at least one arcuate coolant opening 24 in fluidcommunication with a coolant passage 26. However, it should beappreciated that the invention is not limited by the location of thecoolant opening 24 in the toolholder assembly 10, and that the inventioncan be practiced with the coolant opening 24 having any desirable shapeand location. For example, the toolholder assembly 10 can include aplurality of coolant passages 26 in fluid communication with one or morecoolant sources 24 for providing coolant to the side support surfaces20, 22 of the pocket 16, as shown in FIG. 6. In this embodiment, thecutting insert 100 includes a corresponding number of coolant inletapertures 126 in fluid communication with each of the plurality ofcoolant passages 26 formed in the flank faces 108, 110, 112, 114 of thecutting insert 100. It should be realized that, in this embodiment inwhich the coolant inlet aperture is formed in one or more of the flankfaces 108, 110, 112, 114, the coolant outlet aperture is formed only inthe top face 104, the bottom face 106, or both the top and bottom faces104, 106 of the cutting insert 100.

It should be appreciated that the toolholder assembly 10 and the cuttinginsert 100 described above is an exemplary embodiment of the invention,and that the principles of the invention of providing sufficient coolantto the cutting edge-chip interface by forming coolant apertures using alaser technique can be applied to any toolholder assembly and cuttinginsert suitable for use therewith.

For example, the principles of the invention can be applied to a roundtoolholder assembly 10′ and a cutting insert 100′, as shown in FIGS. 7and 8.

The patents and publications referred to herein are hereby incorporatedby reference.

Having described presently preferred embodiments the invention may beotherwise embodied within the scope of the appended claims.

1. A toolholder assembly comprising: a body portion and a cutting endportion extending from the body portion, the cutting end portionincluding a pocket having a bottom support surface and at least one sidesupport surface; a cutting insert mounted in the pocket, the cuttinginsert having a top face, a bottom face opposite the top face, at leastone flank face, a coolant inlet aperture formed in one of the top face,the bottom face, and the at least one flank face, a coolant outletaperture formed in a different one of the top face, the bottom face andthe at least one of the flank face, and an internal coolant passage influid communication with the coolant inlet aperture and the coolantoutlet aperture, wherein the coolant inlet aperture, the at least oneinternal coolant passage and the coolant outlet aperture are formed byusing electro-magnetic radiation; and wherein the cutting insert has acutting edge, and the coolant outlet aperture is formed proximate thecutting edge and is directed towards the cutting edge.
 2. The toolholderassembly of claim 1, wherein one of the coolant inlet aperture, the atleast one internal coolant passage, and the coolant outlet aperture arecircular in cross-sectional shape.
 3. The toolholder assembly of claim1, wherein one of the coolant inlet aperture, the at least one internalcoolant passage, and the coolant outlet aperture are non-circular incross-sectional shape.
 4. The toolholder assembly of claim 1, whereinthe coolant inlet aperture is formed in the top face and the coolantoutlet aperture is formed in one of the bottom face and the at least oneflank face of the cutting insert.
 5. The toolholder assembly of claim 1,wherein the coolant inlet aperture is formed in the bottom face and thecoolant outlet aperture is formed in one of the top face and the atleast one flank face of the cutting insert.
 6. The toolholder assemblyof claim 1, wherein the coolant inlet aperture is formed in the at leastone flank face and the coolant outlet aperture is formed in one of thetop face and the bottom face of the cutting insert.
 7. The toolholderassembly of claim 1, wherein the coolant inlet aperture, the coolantpassage and the coolant outlet aperture have a diameter of between 5microns and 100 microns.
 8. The toolholder assembly of claim 1, whereinthe cutting insert is symmetric with respect to the x-axis, y-axis, andz-axis.
 9. The toolholder assembly of claim 8, wherein the cuttinginsert is generally diamond in shape.
 10. The toolholder assembly ofclaim 8 further comprising a plurality of flank faces, and wherein oneof the flank faces is substantially identical to an opposite flank face,and another one of the flank faces is substantially identical to anopposite flank face.
 11. The toolholder assembly of claim 8 furthercomprising a cutting edge defined at an intersection between the topface and the at least one flank face, and a cutting edge defined at anintersection between the bottom face ant the at least one flank face.